POLYURETHANES MAGAZINE INTERNATIONAL

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1 04/2014 AUGUST/SEPTEMBER POLYURETHANES MAGAZINE INTERNATIONAL VISIT US IN ACHIM, GERMANY! DESMA HOUSEFAIR: Sept 2014 TECHNOLOGY CONCEPT CPI Polyurethanes Technical Conference preview Europur and Euro-Moulders general assembly Bio-based chemicals Natural Oil Polyols Sustainable succinic acid QUADWRAP TRAINER FROM THE IDEA TO YOUR PRODUCT > NEW DESIGN AND PRODUCTION CONCEPT > 100% POLYURETHANE SHOE > INNOVATIVE LIGHTWEIGHT DESIGN > FULLY AUTOMATED MANUFACTURING klöckner desma schuhmaschinen gmbh

2 L. Theunissen, L. Leemans, R. Janssen Properties and performance of Biosuccinium sustainable succinic acid in microcellular polyurethane elastomers Biosuccinium sustainable succinic acid has been evaluated as alternative for adipic acid in the production of polyester polyols used in microcellular polyurethane (m-pu). It is a unique 100 % bio-based product from Reverdia, the use of which increases the renewable content and reduces the environmental footprint of polyurethane formulations, while maintaining the performance required in many applications. During this research, various 2,000 g/mol polyester polyols, all based on ethylene glycol and diethylene glycol mixtures, were synthesised using adipic acid, succinic acid or a succinic/sebacic acid blend. In addition, a commercially available adipate reference (Daltorez P716) was obtained from Huntsman. Synthesis of these polyester polyols was completed without any problems and the resulting properties were within expected ranges. The main difference observed was that the succinate polyol showed some degree of crystallinity, causing a melt temperature (T m ) of approximately 50 C; in comparison, the other polyols were amorphous and showed no transitions other than T g. Compared to adipate systems a higher viscosity of the EDS polyol was observed as well for the polyol based on succinic/sebacic acid blend. Microcellular PU elastomers were prepared based using an MDI prepolymer with an NCO content of 19 %. The ethylene glycol diethylene glycol succinate polyol required minor adjustments for higher processing temperature. Reactivity for all formulations was similar. For performance evaluations, moulded slabs were produced with densities in the range of g/cm 3 ). The succinate elastomer showed a higher hardness compared to the adipate (48 Shore A vs. 37 Shore A). Physical properties like tear strength and elongation at break as well as abrasion resistance were quite similar for all elastomers. Results from this evaluation indicate that Biosuccinium based polyester polyols can be successfully formulated into microcellular polyurethane systems, without the need for extensive revision of formulations to produce materials with very similar mechanical performance to non-bio-based systems. 1. Introduction In the last decade a number of global megatrends have intensifi ed the need for products made from bio-based materials. First, the global upturn on sustainability is driven by the need to respect generations to come and to be careful with the resources that are available. This is leading to more effi cient ways to use, reduce, re-use and recycle materials, and also to using renewable raw materials. Next, the strong growth in demand for oil due to the increasing world population has dominated national and international agendas for many years already. Policy making in several parts of the world is focusing on security of energy supply, now and in the future. Very recently, oil price volatility has Lawrence Theunissen lawrence.theunissen@reverdia.com Dr. Luc Leemans, Dr. Richard Janssen Reverdia V.O.F., Geleen, The Netherlands been particularly large, and has driven many purchasing organisations to search for alternatives. Also, environmental concern has risen strongly in the past ten years. Concern for the planet s wellbeing is at the forefront of the attention of governments, corporations, customers and non-governmental organisations alike. Consumers ever more expect and demand sustainable products. Non-governmental organisations push brand owners to source responsibly and corporations have made sustainability an integral part of their strategies. Renewable materials offer a potential way of improving the sustainable characteristics of the products that are made Tab. 1: Overv iew of polyester polyol formulations and properties Label Diols 1 Diacids Renewable carbon content / % Mn / g/mol from them. All these megatrends have come together, creating a unique situation propelling the growth of bio-based chemicals. 1.1 Biosuccinium In this paper Biosuccinium is investigated as a bio-based alternative for adipic acid (AA) for use in production of polyester polyols and microcellular polyurethane elastomers with an improved environmental footprint. Biosuccinium sustainable succinic acid (SA) is produced by Reverdia, a joint venture between DSM and Roquette, using a proprietary low ph yeast process. It is a 100 % biobased and renewable diacid. Typically, Bio- OH / mg KOH/g AV / mg KOH/g Oven temperature 3 / C Melt 75 C / mpa s EDS EG / DEG SA 59 2, ~70 1,405 EDSS EG / DEG SA / SebA , ,292 EDA EG / DEG AA 0 1, P716 EG / DEG AA 0 ~2,000 ~56.1 < Molar ratio of EG/DEG = 60/40; 2 Molar ratio of SA/SebA = 85/15; 3 Oven temperature used to melt the polyol 252 PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER 2014

3 succinium can be used to substitute adipic acid and could be regarded as a near dropin raw material for the production of polyester polyols and polyurethanes [1, 2]. Reverdia is the fi rst company in the world to have a large scale facility for the commercial production of bio-based succinic acid, which is marketed under its Biosuccinium brand. It benefi ts from the best and most sustainable (yeast-based) fermentation technology [3] to produce bio-based succinic acid, which has been in development since The new production facility with a 10 kt/y capacity is located in Cassano Spinola, Italy, and started operations in December Research objectives Fig. 1: Reduction of the carbon footprint using Bio- succinium versus fossil-based adipic acid [3] Carbon footprint / kg CO 2 -eq/kg acid Biosuccinium 9 Adipic acid The investigation will look at a standard formulation of polyester polyol and microcellular polyurethane elastomers. The differences in manufacturing, processing and properties of the resulting materials versus the adipic acid-based benchmark are to be identifi ed. No optimisation or improvements will be done at this stage, but where possible recommendations for optimisations will be given. 1.3 Enabling sustainable polyurethanes Biosuccinium is made from renewable feedstocks, which requires less from the earth s limited fossil resources, and delivers a reduction in greenhouse gas (GHG) emissions. The use of this materials makes it possible to yield a polyester polyol with a renewable content of up to 60 % and a polyurethane product with a renewable content of up to 30 % (tab. 1 and 2). A calculation of the sustainability improvement potential has been performed for the formulations as prepared in this study. Additionally, an estimate has been made for further improvements by using bio-based raw materials for the diols as used in the polyester polyol, the prepolymer and the chain extender. The Biosuccinium cradle-to-gate study was executed and published by the Copernicus Institute of Sustainable Development at Utrecht University, the Netherlands [3]. The Biosuccinium process uses non-fossil raw materials, sequesters carbon dioxide (CO 2 ), is energy effi cient and the process does not produce unnecessary by-products. Figure 1 shows the carbon footprint of Biosuccinium and the large potential carbon footprint reduction about 8 kg CO 2 -equivalent per kilogram of acid that is possible when substituting fossil-based adipic acid with Biosuccinium. The adipic acid data have been executed by DSM for a best in class plant with 98 % N 2 O abatement. DSM used SimaPro software with EcoInvent database 2.0. Today, different technologies are being employed for the production of succinic acid derived from renewable feedstocks, and each of these has its own characteristics with regards to product quality, operational aspects, and environmental footprint. The Copernicus Institute conducted a Life Cycle Assessment study [3] which in detail compared the various production methods, assuming all other things are equal (especially the energy mix and feedstock usage). They found that the yeast-based fermentation process at low ph, with direct crystallisation, as used by Reverdia to produce Biosuccinium, has signifi cantly lower GHG emissions compared to other fermentation routes as well as petrochemical routes. 2. Experimental 2.1 Materials Tab. 2: Physical properties of moulded PU elastomers Elastomer (polyol) PU1 (EDS) PU2 (EDSS) PU3 (EDA) PU4 (P716) Mix ratio (polyol : prepolymer = 100 :... ) Bio-based content* / % Density / g/cm Hardness / Shore A Stress / 50 % 100 % 200 % break break / % Tear strength / N/mm Tear break / mm Abrasion resistance / mg weight loss 15 n.d n.d * Bio-content originating from the dicarboxylic acids only. Using bio-based EG or DEG will further increase bio-content The raw materials used in this study are shown in table Polyester polyol preparation Polyester polyols with a molecular mass of 2,000 g/mol were synthesised on 3 kg scale in the laboratory by polycondensation of the diacid(s) with a mixture of ethylene glycol and diethylene glycol utilising TBT as the catalyst (tab. 1). The processes were carried out under nitrogen atmosphere by conventional means; fi rst an esterifi cation stage, under atmospheric pressure to 220 C, followed by a PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER

4 polycondensation stage under vacuum to achieve required molecular weight (as measured by product viscosity and hydroxyl value) and an acid value lower than 1 mg KOH/g Polyester polyol properties All synthesised polyester polyols had a molecular mass closely matching the intended 2,000 g/mol. Hydroxyl values and acid values were very low as desired, except for the adipate polyol which showed a somewhat higher acid value of 1.1 mg KOH/g. This higher acid value may have an effect on processing and/or performance of polyurethane elastomers. The EDS polyol showed some crystallinity, with dual melting peaks at 37 C and 47 C (DSC, fi rst heating, see fig. 2). Therefore this polyol required a higher oven temperature (70 C) in order to be melted and processed. The other polyols are amorphous and do not show a melting point (fig. 3, EDSS) and could be melted without problems at the usual temperature of 50 C. Furthermore, both the polyester polyols containing succinic acid showed a viscosity that Tab. 3: Materials is higher than for the adipate reference. This is consistent with reported observations for Biosuccinium polyols for TPUs [1, 2, 4, 6, 7]. The higher viscosity of the EDS and EDSS polyols should be carefully monitored in order to ensure effi cient raw material mixing. The higher melting point of the EDS polyol was not considered to be a problem and could easily be adjusted for. Designation Identification Supplier Bio-based succinic acid Biosuccinium (SA) Reverdia Sebacic acid Sebacic acid (SebA) Dong Feng Adipic acid Adipic acid (AA) Rhodia Ethylene glycol EG Sabic Diethylene glycol DEG Sigma-Aldrich Tetra n-butyl titanate TBT catalyst Acros Adipate polyol (Mn=2000) Daltorez P716 Huntsman MDI prepolymer (NCO=19) Suprasec 2980 Huntsman Activator blend Proprietary Apple Polyurethanes Fig. 2: DSC curve (fi rst heating) of EDS polyol Fig. 3: DSC curve (fi rst heating) of EDSS polyol Glass transition Onset C Midpoint C Delta Cp J/g K Integral mj normalised 4.98 J/g Onset C Peak C Integral mj normalised 4.80 J/g Onset C Peak C Glass transition Onset C Midpoint C Delta Cp J/g K 2 mw Heat flow 2 mw Polyester polyol EDS, mg (1) C, -10 K/min, N ml/min (2) C, 3.00 min, N ml/min (3) C, +10 K/min, N ml/min Heat flow Polyester polyol EDSS, mg (1) C, -10 K/min, N ml/min (2) C, 3.00 min, N ml/min (3) C, +10 K/min, N ml/min Temperature / C Temperature / C Fig. 4: Reactivity evaluation using cup mouldings Fig. 5: Moulded slab after sample punching 254 PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER 2014

5 3. Microcellular PU elastomer preparation Using the above-mentioned polyols, polyurethane elastomers were made with a formulation typically used for a man s shoe, single density unit sole. First, an activator blend was made in bulk by blending chain extender, catalyst, surfactant and water. This activator blend was blended with each polyol using a ratio of 86 parts polyol to 14 parts activator blend. In a next step, a mix was prepared of the polyol blend (heated to C) and the MDI prepolymer (heated to C). Initially, a mixing ratio of 100 : 86 w/w was used, followed by experiments in which this ratio was reduced in 2 % steps. Reactivity was compared using 200 ml cup mouldings (fig. 4), with components mixed using an electric mixer for 10 s. These cup mouldings were used to determine the ratio at which the polyurethanes showed the best foaming behaviour. For performance evaluations, moulded slabs were produced from which test specimens were taken, using the Tab. 4: Overview of PU elastomer compositions and reactivity Elastomer/ polyol PU1/EDS PU2/EDSS PU3/EDA PU4/P716 Cure parameter ratio that gave best reactivity and ±2 %, targeting a density of 0.6 g/cm 3. These slabs had a size of 295 x 97 x ~6 mm (fig. 5), and a theoretical weight of approximately 103 g. Tack-free time, rise time and pinch times (in seconds) were recorded. No cream times were recorded as samples started to cream during or immediately after the 10 s mixing time. Cup cure is assessed by relative permanent indentation at 2 min. Slab cure is assessed by relative indentation using a ballpoint pen tip at 4 min. Both cup cure and slab cure are rated according to the following scale: Full recovery No recovery Good cure Quite good cure Slightly soft Soft Suitability for de-moulding of product was tested after 4 min by bending all slabs on one corner over 90 degrees to observe any surface cracking. For none of the combinations of polyol and mix ratios any cracks were observed. Mix ratio (polyol : prepolymer = 100 : ) Tack-free / s Rise time / s Pinch time / s Cup 2 min Slightly soft Good Quite good Slightly soft Slab 4 min Quite good Good Quite good Soft Tack-free / s Rise time / s Pinch time / s Cup 2 min Slightly soft Good Slightly soft Soft Slab 4 min Quite good Good Good Slightly soft Tack-free / s Rise time / s Pinch time / s Cup 2 min Very soft Quite good Slightly soft Slab 4 min Soft Quite good Soft Tack-free / s Rise time / s Pinch time / s Cup 2 min Soft Good Good Slightly soft Slab 4 min Slightly soft Good Quite good In this study all moulded slabs were demoulded after 4 min. Recent patent literature [5] reports that in some cases succinatebased PU elastomers allow for shorter demoulding times but this effect was not investigated as part of this study. 4. Results and discussion 4.1 Reactivity of polyester polyols EDS polyol Melting the EDS polyol required a temperature of about 70 C. The higher viscosity made it diffi cult to achieve effi cient mixing within the cream time, so moulded slabs have mixing defaults on them. This viscosity is probably diffi cult to process at 50 C on most normal PU shoe soling machines. Reactivity however was slightly faster when compared to the P716 reference (tab. 4) EDSS polyol Also the EDSS polyester polyol has a higher viscosity than P716, but it was mouldable using the process as used in this project. As with the EDS polyol, the viscosity of the polyol blend should be carefully considered to ensure commercial production machine processing and effi cient mixing. The reactivity of this polyester polyol is comparable but slightly lower than P716 (tab. 4) EDA polyol The elastomers based on polyester polyol EDA gave a lower reactivity with longer pinch times and softer cures relative to P716 (also adipate-based). It is considered that this may well be due to the higher acid value of the polyol (tab. 4) P716 polyol (commercial adipate reference) An overview of the adipate PU elastomer composition and the reactivity of reference polyester polyol P716 can be found in table 4. PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER

6 5. Microcellular PU elastomer properties From each of these elastomers, 6 mm thick slabs were moulded from which test specimens were taken for evaluation of hardness, density, and mechanical properties. 5.1 Hardness and density els though. The abrasion resistance of the succinic acid-based elastomer is better compared to the reference, which is obviously highly relevant to wear-resistant, single density unit soles. When slightly increasing the mix ratio of polyol-to-prepolymer for PU1, both density and hardness increase, and overall mechanical properties change accordingly. In terms of abrasion resistance, PU1 (EDSbased) seems to outperform the other elastomers, even when compared to the adipate reference at similar hardness (PU3). For PU2 (based on EDSS) it is comparable to the adipate reference. 5.2 Microcellular PU sustainability characteristics The target moulded density of the slabs was ~0.6 g/cm 3, but since some of the slabs where thicker than 6 mm, the actual density of the moulded slabs varied between 0.47 g/cm 3 and 0.60 g/cm 3. The hardness of the resulting slabs also varied between 37 Shore A and 48 Shore A. As expected there is a correlation between these two, where the higher density slabs also show a higher hardness. From the moulded slabs test samples were taken for evaluation of physical properties, according to the following standardised test methods: Density ISO 1183 Hardness ISO 868 Shore A Tensile behaviour ISO 52 Type 5 Tear strength ISO 34 Trouser Abrasion resistance ISO 9352 H-18 wheel, 1,000 g/wheel, 1,000 cycles PU2 (EDSS) is obtained by incorporating a small amount of sebacic acid into the polyester polyol. The infl uence of the incorporation of this sebacic acid is diffi cult to detect from above results since samples of similar hardness are not available. However, an adipic acid-based reference with similar hardness is available (PU4). When comparing PU2 and PU4, at similar hardness, it can be seen that mechanical properties are almost exactly the same. The differences are very small, and when desired can easily be adjusted for by optimising the polyol-to-prepolymer mix ratio. Based on the above, it is to be expected that both the EDS and the EDSS formulations will lead to practically feasible elastomers, whereas the EDSS formulation will be most comparable to commonly used adipic acidbased formulations Bio-based carbon content of polyols and elastomers In this study, bio-based raw materials have only been applied in the polyester polyols. The use of Biosuccinium succinic acid (in combination with sebacic acid for the EDSS polyol and elastomer) leads to polyester polyols that have a bio-based carbon content as shown in table 5. Mixing this polyol with activator blend (to obtain the A component), and mixing the A component with prepolymer (B component) to obtain the fi nal elastomer, will dilute the bio-based carbon content in the fi nal polyurethane elastomer to 28 % (EDS) and 30 % (EDSS) respectively. The reduction in carbon footprint of the PU elastomer due to the incorporation of Biosuccinium amounts to ~2.3 kg CO 2 -eq/kg PU. As indicated above, both the density and the hardness of the various slabs varied signifi cantly, which in turn also has an infl u- ence on the other (mechanical) properties. In order to be able to draw valid conclusions, it is suggested to compare only slabs of similar density/hardness. Hence, PU3 (EDA) will be used as reference to compare with PU1 (EDS), and PU4 (P716) will be used as a reference to compare with PU2 (EDSS). The differences in properties that are observed seem to correlate quite well with the expected infl uence of different density/hardness of the elastomers, except for the stiffness of PU1, which is higher compared to the other formulations (fig. 6) Opportunities for further increasing the bio-based carbon content When also using Biosuccinium-based polyol in the prepolymer, and using renewable diols When comparing PU1 and PU3 at similar hardness, it can be seen from tensile measurements that the succinic acid-based elastomer has a slightly higher stiffness. The strain at break and the strength, measured in both tensile and tear mode, are slightly lower for the succinic acid-based elastomer. Values are still at practically acceptable lev- Fig. 6: Stress-strain curve for all PU elastomers (mix ratio 100 : 84) Stress / MPa Strain / % PU1 (EDS) PU2 (EDSS) PU3 (EDA) PU4 (P176) 256 PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER 2014

7 and chain extender, the bio-based carbon content of the elastomers can be stepwise increased as indicated below. Bio-based carbon content in fi nal PU elastomer (fig. 7): Bio-polyol in pre-polymer 46 % (+17 %) Bio-EG/DEG in polyester polyol 64 % (+18 %) Bio-BDO as chain extender 70 % (+6 %) This further increase in the bio-based carbon content of the fi nal elastomer is almost independent of the formulation being used (EDS or EDSS). Furthermore, this further increase in the use of renewable raw materials is already feasible today, since bio-based versions of EG, DEG and BDO are available already on the market. 6. Conclusion The work done in this paper shows that Biosuccinium is a feasible alternative for (fossilbased) adipic acid as raw material for polyester polyols and polyurethanes. This enables a potential improvement of the sustainability characteristics of polyester polyols and polyurethane materials because Biosuccinium is a 100 % bio-based and renewable raw material. Moreover, Biosuccinium has a much lower carbon footprint [3] than fossilbased adipic acid about 8 kg of CO 2 -eq/kg of acid which also leads to a substantial decrease of the carbon footprint of the polyurethanes and products made of it. The work presented here is intended to be a reference for a fi rst technical evaluation of Fig. 7: Bio-based carbon content of PU elastomer Bio-based carbon content / % EDS 30 EDSS +17 Bio polyol B component Bio Bio EG/DEG chain extender use of Biosuccinium in a standard formulation of polyester polyol and microcellular polyurethane elastomers. The differences in processing and properties of the resulting elastomers versus the benchmark, adipic acid-based polyesters and thermoplastic polyurethanes, were identifi ed. No attempt was made in any case to optimise or to improve the products, but this is of course very well possible. 6.1 Polyester polyols Various polyester polyols, all based on EG/ DEG glycol mixtures, were synthesised using either adipic acid, succinic acid and succinic/sebacic acid blend. In addition, a commercially available adipate reference was obtained. Synthesis of these polyester polyols of 2,000 g/mol molecular weight were completed without any problems using a standard process for synthesis of adipate polyester polyols. The main difference observed is that the succinate polyol showed some degree of crystallinity, causing a melt temperature (T m ) of approximately 50 C; in comparison, the other polyols were amorphous and showed no transitions other than T g. Compared to adipate systems a higher viscosity of the EDS polyol was observed as well for the polyol based on succinic/sebacic acid blend. 6.2 Polyurethane elastomers Manufacturing of elastomers The crystallinity of the EDS polyol required a slightly higher processing temperature than typical, but that could be adjusted for without problems. The higher viscosity however led to diffi culties in (hand) mixing, and Tab. 5: Bio-based carbon content in polyester polyol and PU elastomer Bio-based carbon content in polyester polyol Bio-based carbon content in fi nal PU elastomer EDS formulation EDSS formulation 59 % 63 % 28 % 30 % should be carefully monitored when using this polyol in commercial production equipment to ensure proper mixing. The EDSS and adipate polyols could be handled without problems. Reactivity for all formulations was similar, with EDS elastomer being slightly faster than the adipate references Properties of elastomers The achieved densities ranged between 0.47 g/cm 3 and 0.60 g/cm 3 with the succinate polyols having a higher density and a higher hardness. The hardness of the resulting slabs varied between 37 Shore A and 48 Shore A. Overall, the physical properties of the elastomers are quite similar. The succinate/sebacate and the adipate-based elastomers are quite similar, the pure succinate elastomers are slightly different on density (higher), hardness (higher), strength and abrasion resistance (both higher). In general, it is expected that experts in the fi eld will fi nd a technically feasible alternative in Biosuccinium sustainable succinic acid compared to fossil-based raw materials like adipic acid. 7. Acknowledgement The authors would like to thank Martyn Bentley, Cromar Solutions Ltd., and Grahame Dowding, Apple Polyurethanes Ltd., for their dedication to this project and the ultimate preparation and syntheses of the elastomers. The synthesis of the polyols, as well as the physical characterisation of the fi nal elastomers, were performed at DSM Ahead. 8. References [1] M. F. Sonnenschein, S. J. Guillaudeu, B. G. Landes, and B. L. Wendt, Comparison of adipate and succinate polyesters in thermoplastic polyurethanes, Polymer 51 (2010) PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER

8 [2] L. J. H. Theunissen, L. Leemans, R. J. M. Janssen, M. Smidt, Evaluating the Properties and Performance of Biosuccinium sustainable succinic acid in Polyester Polyols for Thermoplastic Polyurethanes, paper, Utech Europe Conference, April 2012, The Netherlands [3] B. Cok, I. Tsiropoulos, A. L. Roes and M. K. Patel, (2014), Succinic acid production derived from carbohydrates: An energy and greenhouse gas assessment of a platform chemical toward a bio-based economy, Biofuels, Bioproducts and Biorefi ning, 8: doi: /bbb.1427 [4] L. Theunissen, Biosuccinium based polyester polyols for sustainable polyurethanes, presentation, Utech Europe Conference, April 2012, The Netherlands [5] WO A1, A reaction system for preparing polyurethane microcellular foam, a polyurethane microcellular foam and the use thereof [6] L. J. H. Theunissen, R. J. M. Janssen, R. Miller, Processing & Performance of Biosuccinium and Susterra based TPUs, Proceedings, CPI Polyurethanes Technical Conference 2012 [7] L. J. H. Theunissen, R. J. M. Janssen, Evaluating the Properties and Performance of Biosuccinium Sustainable Succinic Acid based Copolyester Polyols in TPUs : Proceedings, CPI Polyurethanes Technical Conference 2013 Biosuccinium is a registered trademark for bio-succinic acid from Reverdia. Publication information & contacts Publisher Dr. Heinz B. P. Gupta Address Dr. Gupta Verlag Am Stadion 3b, Ratingen, Germany VAT No. DE Postal address P. O. Box , Ratingen, Germany Tel Fax info@gupta-verlag.de Internet Editors Dr. Wolfgang Friederichs (Editor-In-Chief) Dr. Heinz B. P. Gupta Dipl.-Biol. Markus Linden Dr. Stephanie Waschbüsch in memoriam Dipl.-Chem. Frank A. Gupta Freelancer Dr. Stefan Albus (ALS) Angela Austin, M. Sc. (AA) David Vink (DV) Editorial secretary Patrizia Schmidt Tel Advertisement Indira Gupta, Julian Bäumer Tel Subscription Noemi Jäger Tel Layout Ulrich Gewehr, Max Godenrath Tel Frequency of publication 6 issues / year Post distribution no ISSN Bank accounts Deutsche Postbank AG IBAN DE BIC PBNKDEFF Commerzbank Düsseldorf IBAN DE BIC DEUTDEDBDUE Reference to common names, trade names, names of goods, etc., does not warrant the assumption that such names are unrestricted and may therefore be used by anyone. Legally protected registered trademarks are often involved, also when these are not expressly shown as such. Subscriptions, terms of receipt and delivery: Annual subscription fee EUR 120 (6 issues per year incl. delivery costs). Single issue EUR 30 (domestic fees are understood as inclusive of the appropriately valid value added tax). Orders are accepted by the publisher and all national and international book shops. Taking up of a new subscription applies initially for the current calendar year. The subscription is automatically renewed if it is not cancelled in writing six weeks before the end of the calendar year. The subscription fees are invoiced each year in advance and, when participating in direct debit payment, they will be debited automatically. Should the magazine not be delivered due to reasons that are outside our control, there is no right to claim later delivery or reimbursement of subscription fees already paid in advance. The legal domicile for trading is Ratingen, which also applies for all other purposes, insofar as claims for payment are to be enforced. Copyright and publisher s rights: Articles signed with the author s name or signature do not necessarily represent the editor s opinion. Unrequested manuscripts will only be returned if return postage is provided. The publisher requires that the author possesses copyright and rights for use of all constituents of the material submitted, namely also for pictures and tables, etc which are also submitted. With acceptance of the manuscript, the right to publication, translation, re-prints, electronic storage in databanks, additional printing, photocopying and microfi che copying is transferred to the publisher. The magazine and all its contributions and pictures are protected by copyright. All use beyond the limits established by the law on author s copyright is not permitted without approval of the publisher. 258 PU MAGAZINE VOL. 11, NO. 4 AUGUST/SEPTEMBER 2014